Design of a memory based expert system for interpreting facial expressions in terms of signalled emotions
A memory based expert system(JANUS) has been designed to interpret facial expression in terms of the signalled emotion. Janus accepts a geometric description of the face obtained from measurements on a digitised full face photograph and returns the appropriate emotion label. An intermediate representation in terms of verbal face actions(eg. . mouth open,eyes closed)is also used. A production rule system converts the geometric description to verbal form, while a dynamic memory interprets the face actions in terms of emotions. Following the work of Schank(1982)and Kolodner (1984),the dynamic memory is structured as a tree of packets, storing, in Janus, typical facial expressions connected by links to atypical but related face expressions previously encountered. This enables new input to be channelled along the appropriate path to an interpretation based on previous experience. The system is capable of learning new emotion labels and associated face actions for use in subsequent interpretations. A prototype system has been developed on a SUN 2/MJN/120 system using POPLOG.V alidation studies suggest that the interpretations offered by Janus are generally consistent with those of human expert.